Method of slimming radiation-sensitive material lines in lithographic applications

Abstract

A method and system for patterning a substrate using a radiation-sensitive material is described. The method and system include forming a layer of radiation-sensitive material on a substrate, exposing the layer of radiation-sensitive material to a pattern of radiation, and then performing a post-exposure bake following the exposing. The imaged layer of radiation-sensitive material is then developed to remove either a region having high radiation exposure or a region having low radiation exposure to form radiation-sensitive material lines. An exposure gradient within the radiation-sensitive material lines is then removed, followed by slimming the radiation-sensitive material lines.

What is claimed is: 
     
       1. A method of patterning a substrate comprising:
 forming a layer of radiation-sensitive material on a substrate; 
 exposing said layer of radiation-sensitive material to a pattern of radiation, wherein said pattern includes:
 a first region having a high radiation exposure, 
 a second region having a low radiation exposure, and 
 a third region having an exposure gradient ranging from about said high radiation exposure to about said low radiation exposure; 
 
 performing a post-exposure bake following said exposing; 
 performing positive-tone developing by contacting said layer of radiation-sensitive material with a first organic solvent-based composition to remove said first region from said substrate to provide a developed layer of radiation-sensitive material; 
 removing said exposure gradient of said third region by transforming said second region and said third region to a fourth region having a substantially uniform level of radiation exposure, polarity, or de-protection, or a combination thereof; and 
 slimming said fourth region. 
 
     
     
       2. The method of  claim 1 , wherein said layer of radiation-sensitive material comprises:
 a hydrophilic polymer that decreases in polarity upon performing
 said exposing and said post-exposure bake following said exposing of said layer of radiation-sensitive material, 
 an acid wash and a post-acid wash bake of said layer of radiation-sensitive material, 
 a heating of said layer of radiation-sensitive material to a temperature equal to or greater than a thermal decomposition temperature of said radiation-sensitive material, or 
 any combination of two or more thereof; or 
 
 an acid generator that provides acid-catalyzed rearrangement of the hydrophilic polymer to a more hydrophobic polymer upon performing
 said exposing and said post-exposure bake following said exposing of said layer of radiation-sensitive material; 
 said acid wash and said post-acid wash bake of said layer of radiation-sensitive material; 
 said heating of said layer of radiation-sensitive material to said temperature equal to or greater than said thermal decomposition temperature of said radiation-sensitive material, or 
 any combination of two or more thereof. 
 
 
     
     
       3. The method of  claim 1 , wherein said removing said exposure gradient comprises:
 performing a flood exposure and a post-flood exposure bake of said developed layer of radiation-sensitive material; 
 performing an acid wash and a post-acid wash bake of said developed layer of radiation-sensitive material; or 
 heating said developed layer of radiation-sensitive material to a temperature equal to or greater than a thermal decomposition temperature of said radiation-sensitive material. 
 
     
     
       4. The method of  claim 3 , wherein said slimming said fourth region comprises
 contacting said fourth region with a second organic solvent-based composition at an ultra-cold temperature to remove a portion of said fourth region, wherein said ultra-cold temperature is less than 25° C. and greater than a freezing point of said second organic solvent-based composition. 
 
     
     
       5. The method of  claim 3 , wherein said slimming said fourth region comprises contacting said fourth region with a second organic solvent-based composition to remove a portion of said fourth region, wherein said second organic solvent-based composition achieves a rate of a dissolution ranging from about 0.1 nm/sec to about 5 nm/sec. 
     
     
       6. The method of  claim 3 , wherein said slimming said fourth region comprises contacting said fourth region with an aqueous base solution to remove a portion of said fourth region. 
     
     
       7. The method of  claim 3 , wherein said slimming said fourth region comprises contacting said fourth region with an aqueous solution comprising a promoting agent to remove a portion of said fourth region. 
     
     
       8. The method of  claim 7 , wherein the promoting agent is a salt comprising an alkali metal. 
     
     
       9. The method of  claim 3 , wherein said slimming said fourth region comprises contacting said fourth region with an aqueous base solution at a temperature ranging from about 30° C. to about the boiling point of the aqueous base solution. 
     
     
       10. A method of patterning a substrate comprising:
 forming a layer of radiation-sensitive material on a substrate; 
 exposing said layer of radiation-sensitive material to a pattern of radiation, wherein said pattern includes:
 a first region having a high radiation exposure, 
 a second region having a low radiation exposure, and 
 a third region having an exposure gradient ranging from about said high radiation exposure to about said low radiation exposure; 
 
 performing a post-exposure bake following said exposing; 
 performing negative-tone developing of said layer of radiation-sensitive material by contacting said layer of radiation-sensitive material with a first organic solvent-based composition to remove said second region from said substrate to provide a developed layer of radiation-sensitive material; 
 removing said exposure gradient of said third region by transforming said third region, and optionally said first region, to a fourth region formed from said first and said third regions having a substantially uniform level of radiation exposure, polarity, or de-protection, or a combination thereof, wherein said removing said exposure gradient comprises:
 performing a flood exposure and a post-flood exposure bake of said developed layer of radiation-sensitive material; 
 performing an acid wash and a post-acid wash bake of said developed layer of radiation-sensitive material; or 
 heating said developed layer of radiation-sensitive material to a temperature equal to or greater than a thermal decomposition temperature of said radiation-sensitive material; and 
 
 slimming said fourth region by contacting said fourth region with a second organic solvent-based composition, 
 
       wherein said layer of radiation-sensitive material comprises:
 a material that increases in polarity upon performing
 said exposing and said post-exposure bake following said exposing of said layer of radiation-sensitive material, 
 an acid wash and a post-acid wash bake of said layer of radiation-sensitive material, 
 a heating of said layer of radiation-sensitive material to said temperature equal to or greater than said thermal decomposition temperature of said radiation-sensitive material, or 
 any combination of two or more thereof; or 
 
 an acid generator that generates acid upon performing
 said exposing and said post-exposure bake following said exposing of said layer of radiation-sensitive material; 
 said acid wash and said post-acid wash bake of said layer of radiation-sensitive material; 
 said heating of said layer of radiation-sensitive material to said temperature equal to or greater than said thermal decomposition temperature of said radiation-sensitive material, or 
 any combination of two or more thereof; or 
 
 a protected polymer that undergoes de-protection upon heating to a temperature equal to or greater than a thermal decomposition temperature of said protected polymer. 
 
     
     
       11. A method of patterning a substrate comprising:
 forming a layer of radiation-sensitive material on a substrate; 
 exposing said layer of radiation-sensitive material to a pattern of radiation, wherein said pattern includes:
 a first region having a high radiation exposure, 
 a second region having a low radiation exposure, and 
 a third region having an exposure gradient ranging from about said high radiation exposure to about said low radiation exposure; 
 
 performing a post-exposure bake following said exposing; 
 performing negative-tone developing of said layer of radiation-sensitive material by contacting said layer of radiation-sensitive material with a first aqueous base solution to remove said second region from said substrate to provide a developed layer of radiation-sensitive material; 
 removing said exposure gradient of said third region by transforming said third region, and optionally said first region, to a fourth region formed from said first and said third regions having a substantially uniform level of radiation exposure, polarity, or de-protection, or a combination thereof; and 
 slimming said fourth region, 
 
       wherein said layer of radiation-sensitive material comprises:
 a material that decreases in polarity upon performing
 said exposing and said post-exposure bake following said exposing of said layer of radiation-sensitive material, 
 an acid wash and a post-acid wash bake of said layer of radiation-sensitive material, 
 a heating of said layer of radiation-sensitive material to a temperature equal to or greater than a thermal decomposition temperature of said radiation-sensitive material, or 
 any combination of two or more thereof; or 
 
 an acid generator that generates acid upon performing
 said exposing and said post-exposure bake following said exposing of said layer of radiation-sensitive material; 
 said acid wash and said post-acid wash bake of said layer of radiation-sensitive material; 
 said heating of said layer of radiation-sensitive material to said temperature equal to or greater than said thermal decomposition temperature of said radiation-sensitive material, or 
 any combination of two or more thereof; or 
 
 a protected polymer that undergoes de-protection upon heating to a temperature equal to or greater than a thermal decomposition temperature of said protected polymer. 
 
     
     
       12. The method of  claim 11 , wherein said removing said exposure gradient comprises:
 performing a flood exposure and a post-flood exposure bake of said developed layer of radiation-sensitive material; 
 performing an acid wash and a post-acid wash bake of said developed layer of radiation-sensitive material; or 
 heating said developed layer of radiation-sensitive material to a temperature equal to or greater than said thermal decomposition temperature of said radiation-sensitive material. 
 
     
     
       13. The method of  claim 12 , wherein said slimming said fourth region comprises
 contacting said fourth region with an organic solvent-based composition at an ultra-cold temperature to remove a portion of said fourth region, wherein said ultra-cold temperature is less than 25° C. and greater than a freezing point of said organic solvent-based composition. 
 
     
     
       14. The method of  claim 12 , wherein said slimming said fourth region comprises contacting said fourth region with an organic solvent-based composition to remove a portion of said fourth region, wherein said organic solvent-based composition achieves a rate of a dissolution ranging from about 0.1 nm/sec to about 5 nm/sec. 
     
     
       15. The method of  claim 12 , wherein said slimming said fourth region comprises contacting said fourth region with a second aqueous base solution to remove a portion of said fourth region. 
     
     
       16. The method of  claim 12 , wherein said slimming said fourth region comprises contacting said fourth region with a second aqueous solution comprising a promoting agent to remove a portion of said fourth region. 
     
     
       17. The method of  claim 16 , wherein the promoting agent is a salt comprising an alkali metal. 
     
     
       18. The method of  claim 12 , wherein said slimming said fourth region comprises contacting said fourth region with a second aqueous basic solution at a temperature ranging from about 30° C. to about the boiling point of the aqueous base solution.